Stuffing box



Dec. 23, 1941. G. H. WILLIAMS 2,267,183- 4 STUFFING Box l File'd July17, 1939 2 sheets-sheet 1 Y u HH III/ll Dec. 23; 1941. v c-:Lv H,WILLIAMS STUFFING BOX Filed July 17, 1939 2 sheets-sheet 2 f GMW/v H.WML/AMS BY' t A TTORNE Y..

Patented Dec. 23, 1941 ljNlT E D STAT S Zemst ar e r orrice applicationJuly 1c, 1939,l serial Naasama 2y Claims.

My` invention relates to stu-ning boxes and has particularl reference toan improved stuffing box for packing ofi around a reciprecatingrodsuchas the` polished rod of an oil well pump.

In theY pumping off oil wells it is the commonpractice to-emplcyaplungerl and barrel ty'pe of pump located deep within the well, fromwhich a string of sucker rodsextends to the ground surface forconnection toA a reciprocating pumping jack or other power mechanisr-nbywhich the suckerV rods and plunger are reciproca/ted'.

rlhe upper end section oi the sucker rod string is usually formed as apolished red which passes throughv a stuffing box at the well head whichwill prevent leakage of oil' around the polished rod whil'e permittingfree reciprocatory movement thereof. Whilethe ideal condition formaintaining the sealing action of the stuiiing box over prolongedperiods' of operation is that of reciprocating the polishedV rod throughthe stuffing boxin a Vertical linecoincident with the axis of the tubingwithin which it operates, it is found that` this ideal' condition isseldom encountered. The polished rod may be shifted from such axialrelation even though its path of movement may be ina direct Verticalline or the polished rodmay shift laterally during each cycle of itsmovement so that in stuf-iingboxes in which the packing is rigidlymounted such packing',

becomes rapidly worn.

The pumping apparatus which ismost ccmmonly employed for reciprocatingthe sucker rod string is of the walking beam type inv which a walkingbeamis pivoted to reciprocaterina vertical planewith one of its endsdisposed immediately above the well head and-'to which a cable or otherconnecting device is secured and,

coupled to the polished rod. It fellows that,

though thepolished rod will be reciprocated in a substantially verticaldirection, thearcuate path described by the outer end'- of the walkingbeam willi produce a lateral shifting of the-I upper end of' thepolished rod during eachstrokef. Thus the polished redwill be forcedlaterally iirst against one side-'andi then the other of the packingemployed in: the stuft-ing box, rapidly wearing such packing so. thatitV no longer makes a sealing t. with the polished rod. Even thoughdevices suchA as horse headsy are used on the walking beam, tominimizesuch lateral shifting ofthe polished an appreciable shifting irequentlyoccurs with the attendant rapid wearing out of the packing and loss ofseal.

It is therefore an object of my invention to provide a stuing ocx of thecharacter described, in which the packing surrounding the polished rodmay shift laterally in all directions to compensate ior misalignment ofthe power apparatns andy may also assume diiierent angular positionscoincident with the tilt of the axis of the polished rod.

o along the rod and in which` the` packing unit. is ,so mounted within4a, housing; as'to permit. the.l

entire unit: to, shift bodily alli lateral` directions as well as topermit either; end or the pack.'- ing unit to be shifted laterallydifferent amounts l and in diiierent" directionsi Another objecty of myinvention is; to provide a device of: the; character set forth whereinVslide bearings are' provided for eachv endof the; pack:- ing unit uponwhich the packing unit may float ln freely in alli lateral f directionsand in which the "lslidebearings will permit; constant shifting withoutunduey wear. Y

Another object of 'my invention is tor provide a.

device of the character set forth inY the precedingparagra-ph whereinthe bearings are ccnstructed* of' readily replaceable parts.

Other objects and advantages of my invention` will be apparent from astudy of the following specifications, read in connecticn-- with theaccompanyin-g drawings,v wherein Y i' Fig. 1 is a vertical sectionalview takenthrougha stung box construction embody-ing the prin.-

ciples of my invention and-illustrating the position4 of the parts whenthe polished rodl is operating along a direct vertical lineaxially'aligned with the housing; y

, Fig. 2, is a view similar to Fig. 1 but illustrating the position ofthe vparts when the motionl ofthe polished rod isy along a direct.vertical line but is 'i5 oiiset laterally from the axial alignment, withthe housing;

Fig. Sis, a View similar to Fig.. 1 andC illustrating the position oflthe parts when the polished rod is moved along al path which is disposedby 40 an angle tothe vertical or to a changing angle I during difierentparts of the cycle of movement of the polished rod;

Fig. 4 is a diagrammatic View of an oil well pumping apparatusillustrating the circum-V stances of mis-alignment of the pumpingapparatus with the axis of the well, causing the conditions depicted, inFig. 2,; Y

Fig. 5 is a diagrammatic View similar to Fig. 4 and illustrating thecircumstances which cause so a bending of the polished rod and theconditions QQjIhe housing I provides a relatively large diameter"Jfchamber 3 through Which the polished rod Il prises an elongated tubeor sleeve 'I which con-..

stitutes a casing within which is disposed a plurality of packing ring 8formed of suitable packing material. I prefer to arrange the packingrings as relatively narrow rings stacked one upon the other in twogroups, an upper group including a plurality of these rings and a lowergroup including a plurality of these rings, the two groups being spacedapart by means of a, spacing ring 9 illustrated particularly in Fig. 6.

'I'he spacing ring 9 may be readily formed as a casting including anupper ring element I and a lower ring element Il spaced from each otherby a plurality of narrow webs I2 so as to provide therebetween aplurality of relatively large radially extending openings I3 throughwhich lubricant may readily pass to the surface of the polished rodenclosed within the packingrings and spacer rings.

The tubing 'I is preferably somewhat longer than is required to housethe assembled packing and spacing rings so as to provide spaces on eachend of the assembled rings into which glands I4 and I5 (constitutingparts of the packing unit 6) may project, the external diameter of thatportion of the glands I4 and I5 which extends into the tube 'I beingpreferably somewhat less than the internal diameter of the tube 'I sothat while the inner ends of the glands I4 and I5 may bear directly uponthe outermost packing rings there will be substantially no metalliccontact between the glands and the tube 1.

The outer or lower end of the packing gland I4 is preferably machined orground to a horizontal surface I6 which constitutes a bearing surfaceadapted to rest upon and slide laterally on a wear ring I'I which may beformed of relatively hard steel. In order to insure a tight andsubstantially liquid-proof seal between the gland I4 and the wear ringII, the interengaging surfaces may be lapped together.

A similar construction is provided for the gland I5, its upper surface I8 being lapped upon the lower surface of an upper steel wear ring I9.Pressure is applied to the upper gland I5 by means of a cap portion 20of the housing which has a radially inwardly extending shoulder 2Iengaging the wear ring I9, the cap 20 being threadely secured upon thebody portion I of the housing as indicated at 22, so that by screwingdown upon the cap 20 any desired pressure may be exerted upon thepacking rings 8.

It will be observed that the housing I is provided immediately adjacentthe lower end of the gland I5 with an enlargement 23 of its internalbore while the cap member 20 is provided with an internal bore 24immediately adjacent the upper gland I5 of considerably greater diameterthan the greatest diameter of the gland I5. Thus the entire packing unit6 (including the packing rings 8, tubing 1 and glands I4 and I5) areallowed considerable latitude of lateral movement within the housing andcap so that the packing unit is freely iioating in all lateraldirections within the housing.

Moreover, one end of the packing unit 6 is free to float or movelaterally independent of the other end of the unit so that either end ofthe packing unit may shift laterally different amounts and in differentdirections in order to maintain the axis of the packing unit alignedwith a tilted or angular disposition of the polished rod 4.

In Fig. 4 I have illustrated a typical walking beam pumping apparatus ascoupled to the pol- .ished rod 4 and which comprises a walking beam Aarranged to be oscillated about a pivot B by means of a conventionalpitman B. When properly installed, such walking beam A has its outer endC disposed immediately in alignment with the axis of the well bore sothat upon oscillation of the walking beam A the polished rod 4 shouldreciprocate along a direct vertical line which is in turn axiallyaligned with the housing I of the stuiling box. In order that thearcuate path described by the outer end C of the walking beam will notcause appreciable lateral movement away from this direct vertical line,a horse head D may be provided, over which the cable E coupledto theupper end of the polished rod 4 may pass. Under these circumstances thepolished rod 4 will be reciprocated along a direct vertica1 line whichwill be aligned with the axis of the housing I and the position of thepacking unit 6 will be such as is illustrated in Fig. 1. If, however,due to inaccuracy in the construction of the horse head D there is somedeviation from the direct vertical movement, the entire packing unit 6may bodily shift laterally in the housing without imposing any lateralstrain upon the packing and the wear on the packing surface will beuniform throughout its circumference.

However, if there has been any misalignment of the outer end C of thewalking beam with the axis of the well bore, the path described by thepolished rod 4 will be along a direct vertical line but this line willhave been shifted or offset laterally from the axis of the housing I, asis illustrated in dotted lines in Fig. 4. When this condition obtains,the entire packing unit 6 will shift to the position shown in Fig. 2,the packing unit being freely oating within the housing I so that itwill assume the oiset position and again there will be no lateral loadupon the packing rings.

In many wells the actual motion of the polished rod 4 does not follow atrue vertical line as depicted in Fig. 4 but describes a path which isdisposed at an angle to the vertical or which may include a bending ortilting of the polished rod at different portions of its cycle ofmovement. For example, as illustrated in Fig. 5, the cable E may beconnected directly to the outer end C of the walking beam A withoutemploying the horse head D. The arcuate path described by the outer endC of the walking beam will therefore cause the polished rod 4 to assumedifferent angular positions during different portions of its cycle ofoperations so that within the stufling box the polished rod isreciprocated along a path of constantly changing angle to the vertical.By employing my stuffing box with the packing unit freely floating ateach of its ends, the packing unit may assume constantly changingangular positions, maintaining the packing unit in alignment with theaxis of the polished rod, as shown in Fig. 3. To facilitate this angulardisposition of the packing unit, I prefer that the packing glands I5 andI 8 be formed with tapering side walls as indicated at I 4a and I5a,respectively, which will permit the sleeve 'I to assume the necessaryangular position without requiring tilting of the glands I4 and I5.Under such conditions it will be apparent that the glands I4 and I5 willeach slide laterally to whatever extent is required to maintain thepacking unit in axial alignment with the polished rod 4 and no lateralload will be imposed upon the packing rings 8.

It will be observed, from an inspection of Figs. l, 2 and 3, that a wearbushing 25 is provided to encircle the polished rod 4 immediately abovethe steel wear ring I9, the wear bushing 25 being received within achamber 26 formed in the upper end of the cap or cover` member 2U. Theshape of the chamber 26 is such that it provides a radially inwardlyextending flange or shoulder 2l, overlying a radially extending flange28 formed upon the wear bushing 25, but the shape of the chamber 26 issuch that all of its lateral diameters considerably exceed thecorresponding diameters cf all portions of the wear bushing 25. rIhelateral space which is therefore provided through which the wear bushing25 (and the polished rod 4) may shift are maintained, however, slightlyless than the lateral space provided in the chamber 3 through which thepacking unit may shift. Hence where mis-alignment exceeds the amountwhich may be compensated for by the shifting of the packing unit, thewear bushing will engage and bear upon the cap 29 so that any wear whichoccurs, occurs immediately between the wear bushing 25 and the polishedrod 4 Where it may be readily noticed and suitable correction inalignment may be made. By forming the wear bushing 25 of cast iron orsimilar material softer than the polished rod 4, all of the wear whichoccurs prior to correction will occur on the Wear bushing 25, whichbushing is readily replaceable. However, even though such wear doesoccur, there will be no lateral strains imposed between the packing unit5 and the polished rod 4 and there will be no loss of seal between thesemembers.

By providing the packing rings 8 freely floating within the shell ortube 1, any bending which may occur in the polished rod during itsnormal reciprocating motion may be compensated for by the relativelateral shifting of the several packing rings to conform with the bendproduced in the polished rod 4. A

Lubrication of the entire stuffing box may be readily accomplished byfilling the chamber 3 with suitable oil, grease or other lubricant,which may be introduced through a suitable grease fitting 29 extendinginto the cover 29. Adequate lubrication of the polished rod may belikewise accomplished by providing a plurality of holes or apertures Silthrough the shell 'I which are alignable with the space between theupper and lower flanges of the spacing ring 9 so that lubricant may passfrom the chamber 3 through the openings in the shell I and through theapertures I3 provided in the spacing ring 9 to the surface of thepolished rod 4.

It will be observed that the bore 3| through the ring 9 is somewhatlarger than the diameter of the polished rod 4 so that the interior ofthe ring 9 forms a lubricant chamber immediately adjacent the surface ofthe polished rod.

Since the shell 'I is not secured either to the glands I4 and I5 or thepacking rings 8 and therefore may assume various vertical positionsrelative to the spacing ring 9, I prefer to provide a plurality of setsof holes or apertures 30 in the shell 'I arranged in staggered relationabove and below the central set of such apertures so that regardless ofvertical shifting of the shell 'I at least a number of holes will bedisposed adjacent the apertures I3 in the spacing ring 9.

It will be apparent that the stuii'ing box constructed in accordancewith the description herein may be readily and economically manufacturedsince the glands I4 and I5 may be constructed as duplicates of eachother and the steel bearing rings I 1 and I9 may be constructed asduplicates. Moreover, it will be noted that the entire packing unit maybe readily removed and replaced merely by removing the cover portion 20of the housing, all of the parts of the packing unit and theirassociated wear rings being readily removable through the upper end ofthe chamber 3.

It will therefore be observed that I have provided a stuffing box forpolished rods which will automatically compensate for any of the lateraldisplacements commonly found in oil well pumping apparatus and that, byproviding the freely floating packing unit, I insure an adequate packingseal regardless of the cause, character or degree of such lateraldisplacement.

While I have shown and described the preferred embodiment of myinvention, I do not desire to be limited to any of the details ofconstruction shown or described herein, except as defined in theappended claims.

I claim:

1. A stuiiing box comprising a housing through which a reciprocating rodextends, a packing unit surrounding said rod and extendinglongitudinally along said rod, plane bearing surfaces formed at eitherend of said packing unit and disposed transversely of the axis of saidrod, a chamber formed in said housing having lateral dimensions inexcess of the lateral dimensions of said packing unit, plane bearingsurfaces formed upon said housing at opposite ends of said chamber toengage and mount said packing unit for free bodily lateral movementwithin said chamber, a wear bushing surrounding said rod, and a secondchamber in said housing for receiving said wear bushing having lateraldimensions exceeding the lateral dimensions of said bushing by an amountless than the dimensions of the first chamber exceeds the dimensions ofthe packing unit.

2. A stuffing box comprising a housing defining a chamber through whicha reciprocating rod extends in the general direction of the longitudinalaxis of the chamber; a packing unit surrounding said rod including apair of glands spaced free of each-other along said rod, a plurality ofseparate packing rings surrounding said rod and interposed between saidglands, each of said glands comprising a bushing having an inner endengageable with said packing rings and an enlarged outer end, alongitudinal rod receiving bore extending through said gland and havinga plurality of diameters al1 in excess of the diameter of said rod,progressively increasing from the inner end to the outer end of saidgland, the outer end of said gland having a plane bearing surface formedthereon and disposed in a plane perpendicular to the axis of said bore,a sleeve surrounding said packing rings and of greater length than saidpacking rings to overlie the inner ends of said glands, said glandshaving an outer surface tapering inwardly as it approaches the outer endof said gland to permit axial misalignment of said sleeve with saidgland, and plane bearing surfaces on said housing disposed adjacent eachend of said chamber and extending in a plane perpendicular to the axisof said chamber for slidably mounting said glands for free lateralmovement independent of each other.

GLYNN H. WILLIAMS.

